ABSTRACT
AIM: The temporal pattern of bone-level alterations in conventionally restored implants is dependent upon healing mode (open or submerged). This study examined the influence of healing on marginal bone levels at implants with a medium-rough surface including the implant collar and a clearance-fit implant-abutment connection restored according to a platform-switching concept. MATERIAL AND METHODS: Two implants were placed in the posterior mandible of 21 test subjects, randomly assigned to open (OH) or submerged (SH) healing. Standardized radiographs were obtained after implant surgery, before re-entry, after crown mounting, 1 and 2 years after implant surgery, and evaluated for implant-bone-level alterations (ΔIBL). Bacterial samples of the implants' inner cavities were analysed by cultivation. STATISTICS: Brunner-Langer Model, equivalence testings by Wilcoxon's (equivalence range ±0.4mm). RESULTS: After 2 years, ΔIBL were -0.47±0.46mm (OH) and -0.54±0.38mm (SH). At the 1-year follow-up, all implants were contaminated with bacteria. ΔIBL (p<0.001) and the amount of bacterial contamination (p<0.001) significantly depended on time, but not on healing mode. ΔIBL of OH and SH were equivalent at all time points (all p0.044). CONCLUSIONS: Platform-switched implants showed very limited peri-implant bone-level alterations. The healing-mode neither affected the total amount nor the temporal patterns of ΔIBL. Thus, the results for the tested implants with a non-rigid implant-abutment connection were similar to results reported previously for implants with a rigid implant-abutment connection.
